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midnite
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 Posted: Wed May 18, 2022 4:40 pm Post subject: ZFS: What is kernel "static installs"? |
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Previous subject: Cannot create zpool: feature 'dedup' unsupported by kernel ?
[SOLVED] dedup is a zfs filesystem property, rather than a zpool feature. We can also specific it while zpool create by -O, the capital letter O.
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| I am using the Gentoo 5.15.26 kernel. Sort of new and basic kernel.: | % eselect kernel show
Current kernel symlink:
/usr/src/linux-5.15.26-gentoo |
| I wish to create zpool with deduplication. But it complains ...: | # zpool create -o feature@dedup=on zpool_baze mirror /dev/sda /dev/sdb
cannot create 'zpool_baze': feature 'dedup' unsupported by kernel |
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May be related. May be not.
Reference to the ZFS wiki, I am not sure why I do not have CONFIG_SPL. What does SPL means? What does CONFIG_SPL do?
https://wiki.gentoo.org/wiki/ZFS#Advanced
| Code: | % grep -ie _zfs -ie _spl /usr/src/linux/.config
CONFIG_SPLIT_PTLOCK_CPUS=4
CONFIG_ARCH_ENABLE_SPLIT_PMD_PTLOCK=y
CONFIG_ZFS=y |
In addition, what does "static installs" means? Does it mean not using the "Distribution Kernel"? I do not prefer using Distribution Kernel.
| Quote: | | Installing into the kernel directory (for static installs) |
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Last edited by midnite on Thu May 19, 2022 7:01 am; edited 2 times in total |
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alamahant
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Joined: 23 Mar 2019
Posts: 3879
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| Posted: Wed May 18, 2022 4:59 pm Post subject: |
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Hi
zfs is not native to the kernel tree.
You install it by
This will pull the zfs-kmod ie the zfs kernel modules along with the zfs userspace utils and also the so called "spl".
It means
Solaris Porting Layer (SPL) and is a Linux kernel module which provides many of the Solaris kernel APIs.
See my /usr/src
| Code: |
ls /usr/src
linux linux-5.12.9-gentoo linux-5.13.13-zen linux-5.16.2-gentoo linux-5.17.1-gentoo-r1 spl-2.1.99 zfs-2.1.99
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Therefore you do NOT need and in fact should not include any zfs-specific config in your .config.
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midnite
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Posts: 435
Location: Hong Kong
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| Posted: Wed May 18, 2022 5:24 pm Post subject: |
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Thank you for reply, alamahant.
I am sorry I forgot to mention I have already installed zfs and zfs-kmod. After kernel compile, I have also rebuilt modules, rebuilt initramfs (this is not related), and reboot.
| Code: | # qlist -vIRUS zfs
sys-fs/zfs-2.1.4:0::gentoo -custom-cflags -debug -dist-kernel -kernel-builtin -minimal nls pam -python -python_targets_python3_10 -python_targets_python3_8 python_targets_python3_9 rootfs split-usr -test-suite -verify-sig
sys-fs/zfs-kmod-2.1.4-r1:0::gentoo -custom-cflags -debug -dist-kernel rootfs -verify-sig |
But I still cannot create zpool with the dedup option. Without dedup option, it is ok.
| alamahant wrote: | | Therefore you do NOT need and in fact should not include any zfs-specific config in your .config. |
Do you mean I should inculde CONFIG_SPL and CONFIG_ZFS as modules? I need ZFS on Boot, on Swap, and on Root.
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alamahant
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| Posted: Wed May 18, 2022 6:41 pm Post subject: |
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It means in your /usr/src/linux/.config you should NOT include any zfs clauses.
No CONFIG_SPL and CONFIG_ZFS nothing.
As for the dedup issue there is no feature to be specified @creating zpool.
Rather you enabled it afterwards.
| Code: |
zpool create -o feature@dedup=on zpool_baze /dev/sdc22 -f
cannot create 'zpool_baze': feature 'dedup' unsupported by kernel
zpool create zpool_baze /dev/sdc22 -f
zfs get dedup zpool_baze
NAME PROPERTY VALUE SOURCE
zpool_baze dedup off default
zfs set dedup=on zpool_baze
zfs get dedup zpool_baze
NAME PROPERTY VALUE SOURCE
zpool_baze dedup on local
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| Code: |
I need ZFS on Boot, on Swap, and on Root.
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Ok plz follow the procedure about root-on-zfs.
I like this
https://openzfs.github.io/openzfs-docs/Getting%20Started/Debian/Debian%20Buster%20Root%20on%20ZFS.html
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midnite
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Posts: 435
Location: Hong Kong
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| Posted: Thu May 19, 2022 5:44 am Post subject: |
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Thank you very much alamahant for testing it for me. It works for me now to enable it afterwards. Thank you also that I have read through the openzfs installation docs. I find out that dedup is a zfs filesystem property, rather than a zpool feature. We can also specific it while zpool create by -O, the capital letter O.
| Code: | | zpool create -O dedup=verify -O atime=off -O xattr=sa zpool_baze mirror /dev/mapper/luks_yyyymmdd_xxx /dev/mapper/luks_yyyymmdd_yyy |
As for CONFIG_SPL and CONFIG_ZFS, I just notice I have the /usr/src/spl-x.x.xx and /usr/src/zfs-x.x.xx directories too. They are new to me. May I ask what are they? They do not seem like kernels.
| Code: | # ls /usr/src/
linux linux-5.10.100-gentoo linux-5.10.52-gentoo linux-5.10.76-gentoo-r1 linux-5.10.88-gentoo linux-5.10.93-gentoo linux-5.15.11-gentoo linux-5.15.16-gentoo linux-5.15.23-gentoo linux-5.15.26-gentoo linux-5.15.32-gentoo-r1 spl-2.1.4 zfs-2.1.4 |
Sorry to ask this over and over again. It is because it seems strange to me. CONFIG_ZFS enables ZFS filesystem support in the kernel. Should I really disable it?
Back to the Gentoo ZFS wiki. May I know what does "static installs" mean?
https://wiki.gentoo.org/wiki/ZFS#Advanced
| Code: | ┌────────────────── Search Results ───────────────────┐
│ Symbol: ZFS [=y] │
│ Type : tristate │
│ Defined at fs/zfs/Kconfig:1 │
│ Prompt: ZFS filesystem support │
│ Depends on: BLOCK [=y] && EFI_PARTITION [=y] │
│ Location: │
│ (1) -> File systems │
│ Selects: ZLIB_INFLATE [=y] && ZLIB_DEFLATE [=y] │ |
Edit:
I found this discussion about the Gentoo ZFS wiki about the "Installing into the kernel directory (for static installs)" section. Some suggest that we can simple skip that section.
https://linux.gentoo.user.narkive.com/q29uemW5/gentoo-user-zfs-wiki-confusion
During their discussion 9 years ago, there was a -static-libs USE flag at sys-fs/zfs. We do not have it anymore. Is it related to the "static installs"?
| Quote: | 'emerge zfs' shows:
Calculating dependencies... done!
[ebuild N ] sys-fs/zfs-0.6.1 USE="rootfs -custom-cflags
(-kernel-builtin) -static-libs -test-suite" 1,500 kB
[ebuild N ] sys-fs/zfs-kmod-0.6.1 USE="rootfs -custom-cflags -debug"
0 kB
[ebuild N ] sys-kernel/spl-0.6.1 USE="-custom-cflags -debug
-debug-log" 209 kB |
| Quote: | | ah! so the 'static' is a reference to non-modular kernel builds. got it. |
"Static installs" means compiling CONFIG_ZFS into the kernel, rather than build as module?
If we did not run the ./copy-builtin command in that section, I guess we will not have the /usr/src/spl-x.x.xx and /usr/src/zfs-x.x.xx directories.
If we are using ZFS for ROOT, as well as BOOT, we will need ZFS support in the initramfs. I think this needs ZFS be turned ON in the kernel, so that ZFS support will be pulled into the initramfs. Is this understanding correct?
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alamahant
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| Posted: Thu May 19, 2022 9:35 am Post subject: |
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| Quote: |
Sorry to ask this over and over again. It is because it seems strange to me. CONFIG_ZFS enables ZFS filesystem support in the kernel. Should I really disable it?
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I use zfs without any problem whatsoever.
Here is my .config
| Code: |
grep -i zfs /usr/src/linux/.config
<nothing-to-show>
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| Quote: |
If we are using ZFS for ROOT, as well as BOOT, we will need ZFS support in the initramfs. I think this needs ZFS be turned ON in the kernel, so that ZFS support will be pulled into the initramfs. Is this understanding correct?
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Not quite. Grub and the initrd(preferably dracut) will handle all that.
Its the same like for example ext4 configured as module.
It is contained in the initrd to enable mounting the / partition.
If you are not using initrd then yes you need it in-built in the kernel.
| Quote: |
As for CONFIG_SPL and CONFIG_ZFS, I just notice I have the /usr/src/spl-x.x.xx and /usr/src/zfs-x.x.xx directories too. They are new to me. May I ask what are they? They do not seem like kernels.
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They contain kernel modules originally from solaris and needed for zfs to function in Linux.
https://github.com/openzfs/spl
| Quote: |
During their discussion 9 years ago, there was a -static-libs USE flag at sys-fs/zfs. We do not have it anymore. Is it related to the "static installs"?
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In my very limited understanding "static-libs" means all libs needed for a binary to function are included built-in in the binary as opposed to dynamically linking to them at runtime.
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Last edited by alamahant on Thu May 19, 2022 9:58 am; edited 5 times in total |
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midnite
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| Posted: Thu May 19, 2022 9:42 am Post subject: |
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I see. Thank you alamahant for clarification. I will try it out.
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